Utilização do dióxido de cloro e do ácido peracético como substitutos do hipoclorito de sódio na sanitização do cheiro-verde minimamente processado

Abstract

Minimally processed vegetables are ready to eat products that should be free of pathogenic microorganisms. These vegetables must be washed in good quality water, followed by the addition of a sanitizer to reduce the microbial count and minimize the product's deterioration, increasing its preservation and making it microbiologically safer. Sodium hypochlorite is the only sanitizer for this purpose allowed by Brazilian legislation. Although efficient, its use has been questioned because it is a precursor of organic chloramines, compounds of high carcinogenic potential. Many sanitizers have been proposed as substitutes of sodium hypochlorite in the disinfection of vegetables, including chlorine dioxide and peracetic acid. Therefore, based on microbial analyses, this research aimed to test the efficiency of chlorine dioxide (10, 25 and 50 ppm /2, 5 and 10 minutes) and peracetic acid (60, 80 and 100 ppm/5, 10 and 15 minutes) in comparison with sodium hypochlorite (120 ppm/15 minutes) in the control of natural microbiota of minimally processed green seasoning. The green seasoning, which consists of fresh parsley and welsh onions, was washed in various concentrations of sanitizing solutions for given times and then processed to obtain sample of green seasoning. The control sample was washed only in tap water. The treatments were repeated on 3 distinct occasions at 4-month intervals, and 3 samples (packages of 150 g) were collected from each treatment for microbial analysis of pathogenic Salmonella sp., total coliforms, Escherichia coli and total fungal count. The results of these analyses after statistical evaluation indicated that higher concentrations and longer sanitizing treatments led to better microbial control. However, according to the standards in the current legislation on Salmonella sp. (absent from 25 g of sample) and E. coli (≤ 2 logUFC.g-1), all the samples analyzed here were suitable for consumption except for the control, washed only in water. In addition, peracetic acid proved more efficient than sodium hypochlorite, while chlorine dioxide did not show any advantage over sodium hypochlorite. Nevertheless, both sanitizers (chlorine dioxide 50 ppm/10 minutes and peracetic acid 80 ppm/5 minutes) proved suitable substitutes of sodium hypochlorite (120 ppm/15 minutes).